A conventional automobile plate blanking method is die blanking, and a steel plant or an entire car plant generally has an automatic uncoiling-cutting-stacking production line. The apparatus comprises a conveying unit, a press unit and a stacking unit.
With the above-mentioned die blanking method, a material sheet of a simple shape (such as a rectangular, trapezoidal or arc shape) can be processed by way of swing-cutting, and a material sheet of a complex curve shape is processed by die blanking. It is required to provide the blanking line with different blanking dies depending on the size of a material sheet of a vehicle model, and to produce different material sheets by exchanging the dies. In the automobile manufacturing field, the metal plate blanking line has a very high operation efficiency, generally of 4,000,000-6,000,000 sheets per year. It is about 25 sheets per minute on average, on the basis of 3,800 hours per year.
However, although the above-mentioned die blanking method is suitable for large-scale mass production of ordinary vehicle models, there are still certain limitations, especially the following problems:
high costs in manufacturing and storing blanking dies; high space requirements for die stacking and maintenance room; and plant building investments due to large press equipment and equipment foundation. Particularly, for a small-batch production of some personalized vehicle models, the above-mentioned die blanking method is uneconomic.
In recent years, with rapid development of the laser technology, the cutting speed (for a steel plate with a thickness less than 1.5 mm, the cutting speed can be kept not less than 20 m/min when using a 4 KW optical fiber laser generator) and photoelectric conversion efficiency (more than 20% at present) of laser rays are continuously increasing, so that the laser cutting cost reaches a critical point so as to make it possible to apply laser cutting to large-scale blanking machining of profiled sheet metals.
It is known that some companies and research institutes at home and abroad have begun to study laser blanking of automobile plates. For example, Chinese patent CN 102105256 A to Automatic Feed Company provides a progressive laser cutting device for high-speed cutting. In the device provided in this patent, on each door frame, at least one movable laser head performs a laser cutting operation. However, this method has many technical difficulties; for example, simultaneous operation of multiple cutting heads can hardly ensure alignment of cuts generated by cutting operations of multiple devices, and a deviation in the plate shape will affect the cut shape. Huge configuration and occupied area of multiple sets of laser cutters and cutting units also cause a high equipment investment.